Quick-acting switch



Jamzz, 1929. 1,699,792

E. P. LARSH QUICK ACTING SWITCH @www Jan. 22, 1929. 1,699,792 E. P.LARsH QUICK ACTING SWITCH Filed Oct. 19, 1925 2 Sheets-Sheet 2 PatentedJan. 22, 1929.

UNlTElll STATES PATENT OFFICE. i

EVEREIT P. LARSH, F DAYTON, OHIO, .ASSIG'NOR TO THE MASTER".IILIE.C'JILIGOOM-` PANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.`

QUICK-ACTING SWITCH.

Application le. October 19, 1925. Serial No. 63,393.

My invention relates to electric s'vvitches and more particularly to anautomatic quick acting cut-out for alternately opening and closingyelectric circuits under influencent variations of pressure, temperatureor intensity of an actuating medium. lhile invention herein shown anddescribed more particularly in its application to electric switches, itwill be understood that the same actuating mechanism [may be utilizedfor opening and closing a valve, shifting a clutch intoor out ofoperative position, or to perform other analogous operations. a

A very usual application of the present type of automatic cut-out isintheeontrol of motor driven pumping systems for Water distribution. lnsuch installations, it is customary to store Water and air in a suitabletank or reservoir, by means of a motor driven supply pump, dischargingunder sufhcient pressure that the water may be carried through the pipelines of the distribution system by the influence of air pressure Withinthe tank or reservoir. Control or cut-out devices are utilized in suchsystems to maintain the pressure Within prescribed limits by setting thesupply pump in operation when the pressure Within the tank anddistribution system falls below a predetermined range and to arrest thesupply pump when the pressure has been restored, to a predeterminedmaximum degree. In many instances these control devices have been of aslow actingtype, having a tendency to dwell or lag in a partiallyoperated `condition. The present construction is designed to not onlyovercome this objection by providing a construction which will maintaina full or even increased pressure upon the contact until the instant ofbreakage, Whereupon the disconnection or breaking movement vvill beefected with a quick snap-over action,eliminating any tendency to sparkor arc between the contact points.

Theobject oi the invention is to simplify the structure as Well as themeans and mode oi! operation of such quick acting cut-out mechanisms,"whereby they Will not only be cheapened in construction, but will bemore efficient in use, positive in operation, uniform in action,automatically controlled, and unlikely to get out of repair.

A 'further and important object of the invention is to provide such amechanism having a minimum number ofparts so shaped and designed thatthey may be economically manufactured by stamping` orpunch pressoperations and so arranged as to facilitate assembly. Simplicity ofconstruction and economy of manufacture are of prime importance.

With the above' primary and other incidental objects in vie\v,as vvillmore fully appear in the specilication, the invention con`- sists of thefeatures of construction, the parts and combinations thereof, and themode of operation or their equivalents as hereinafter described and setforth in the claims.

Referring t-o the accompanying drawings, wherein is shown the preferred,although obviously not necessarilythe only form of embodiment of theinvention, Fig. 1 is a side elevation of the assembled mechanism,showing the switch in its open or retracted position. Fig, 2 is asimilarview illustrating the relative relation of the parts upon reversal ofthe movement, the switch being shown in its operated or closed position.

Fig. 3 is a detail elevation of the operating members, viewed at rightangles from the left in Figs. l and. Fig. l is a detail perspective viewof the actuating parts in' their assembled relation. Fig. 5 is a detailperspective vien7 of the several operating parts disassembled. `lligs.G, and "-8 'illustrate different modes of operation, to Wit:` iloatactuated, thermostatic operated and by use of a sylphon or expansionchamber, respectively. Fig. 9 illustrates the use of rigid contactcarrying arms in lieu of the spring arms of the primary construction.Figs. l0 and l1 illustrate the Vapplication of the apparatus to theoperation of a valve and a clutch respectively. Like parts are indicatedby similar characters of reference throughout the several views. y

The operating mechanism of the present cut-out is enclosed Within ahousing or case l, in the base of which, there is provided an expansiblechamber 2, formed by the transverse diaphragm 3, the margin of which isprovided with `a bearing plate l, provided with a central boss '7,engaged by the arm of the rock lever. The arm 5l of the rock lever isthus `sulaj eeted to. yupward pressure of the diaphragm, and is .alsosubiect to yielding resistance of a helical spring 8, bearing upon theouter end of the lever kin oppos1- tion to the influence of thediaphragm. lhe tension or resistance of the spring 8 maybe regulated bya screw stud 9 engaged in the upper portion of the nhousing '1,;andbearing upon a disc or head 10, against which the upper end of' thespring reacts. For convenience of assembly the bell crank lever 5 'isprovided with a notch 11, at its inner angle for engagement upon thetrimmen stud, or shatt L Pivoted `upon the same Y trunnion stud t andpositioned within the extends.

channel of the upstand'i'ng `arm 5 oi? the bellcrauk lever,` is acam arm12, having oppositelgy inclined or divergent cam faces at its upper end.The cam arm 12 "is provided with L ilotcli or recess 13, into which theupperend of the arm 5 oi: the bell crank lever YThis notch 13` ofsufficient dimension to permit a limited play or rela tive movement ofthe cam arm and bell crank lever relative one to the other, but

t beyond which limited range of movement,

'the cam arm` and bell Crank level: move in unison in either direction.

The movable switch contacts 14 are carried upon spring` arms 15, whichare. flexed to. and `iro to carry the contacts into and out ofelectrical engagement with stationary contacts 16, mounted upon a wallor plate 17 of ber Or other insulating material, se-

cured within `the housing l. The spring 15 are termed at midlength pointwith Vbights 1S, in which is engaged a transverse tie-rod 19. Thistie-rod 19 is preferably provided adjacentV its. ends with shallowgrooves,4 within which the bights of the re s ect-ive springs 15 arecontracted, to locate tie springs u on the tie rod and secure them inrelationA t rewith. Engaged upon the tie rod. 19 intermediate the springai'tn'is l5 is a plunger member 20, capable of to and fro movement in`unison with the flexing of `the spring arms 15, necessary to make andbreak the electrical contact between the con,- tact heads. 14 and 16,and also capable oli' `oscillatory or rocking movement about the tie rod19. The plunger 20` carriesfa roller 2l, which is engageable lrst withone inclined side and then with the other of the .upper end of the canibar 12J. The plunger member 20 isdepressed and the roller 21 `held incontact with the engaged inclined face of the cam bar and is forceddownward thereon by thepressuae of the helical spring 22bearing atitslower end upon the plunger member 20 and reacting at its upper endagainst .the interior ofthe top of the housing l. The camming action ofthe inclined face oppositely inclined head of the arm.

ofthe cam bar 12 as theroller 20 is forced downwardly thereon underinfluence of the spring 22 tends to move the plunger 20 to `and fro toopen or close the switch Contact. In the opening movement or retractionof' the plunger 20 as shown in Fig. l, its movement is Vlimited by thestop stud 23, projecting from the housing l. In its opposite or closingmovement, as illustrated in Fig. 2, the movement of the plunger islimited only by the contact pressure of the switch contact heads 14 and16. The differential mechanism is actuated by variations or' pressurewithin the diaphragm chamber 2, which is connected' with any suitablebody of lluid under fluctuating pressure. This diaphragm chamber 2 maybe connected with the storage reservoir of a water distribution system,or it may be in communication with a body of expansible and contractible`fluid subject to variations of temperature as for instance, inV arefrigerator, whereby the switch will be operated to stop and start therefrigerating apparatus. In lieu of such pressure variations, theapparatus may be actuated 'by a rise and fall of a float, or by thetension of a thermostatic bar or the like.

Assuming the parts to be in the position shown in Fig. 2, any upwardpressure upon the arm 5l of the bell crank lever 5 tends t0 oscillatethe bell crank lever toward theright against the yielding resistance ofthe spring 8. The upper end of the arm 5 of the rock lever being engagedin the notch 13 of the cam arm l2, carries with it the cam arm, theinclined upper end of which bears against the roller 21 ol' the plunger20. This camming pressure of the inclined' head of the arm 12, upon theroller 21, not only tends to move the plunger 20 toward the right andthereby increase the Contact pressure between the switch contacts 14:and 16, but it exerts an upward or rocking influence upon the plunger20, against the yielding resistance of the spring 22. It will be notedthat the downward pressure of the spring 22 is in a somewhat inclineddirection,` in which it adds its influence to that of the cam in holdingthe switch elements in engaged relation. The contact elements are thusheld in tight engagement with gradually increasing pressure until in themovement of the rock lever and cam arm, the roller 2l reaches the apexoit the To prevent any dwell or lag of the parts at this stage, and toafford a quick snapfozver action, by which the contact is definitelybroken without hesitation, the cam arm 12 is permitted a slight movementindependent of the rocker arm, within the limits afforded by theclearance of the notch 111. The apex of the cam arm is thus passedentirely past the roller 21, and the roller 2l is forceddown theopposite incline of the head of the cam arm, by the reaction of thespring 22, which lll .Uli

l ce

1 plements that of the diaphragm pressure in overcoming the resistanceof the main spring S, and completing the retractive movement of the v)lunger 20 and the spring switch arms 15. The parts at their finalmovement as-l sume the position shown inFig. 1. Upon lecrease ofpressure beneath the diaphragm,

the expansive influence of the spring 8 is exerted to rock the `bellcrank lever 5 in the opposite direction against the yielding resistanceof the spring 22, which is compressed by the camming action of theinclined head ot the cam arm 12 uponthe roller 21, as the rollerandplunger 2O are elevated until the apex of the cam head passes beneaththe roll er. rlhereupon the cam arm is again permitted a slightindependent movement suilicient to obviate any tendency to lag andpresents thejopposite inclined face of the cam head to the roller. lnits movement to andl fro, the plunger 2O passes a dead center relationrelative to the spring 22, so that the spring 22 exerts its influencediagonally, first in one direction and then in the other, to hold theswitch contact open or closed. ln this manner, the cam action and springtension are complementary of each other, and operate in unison to e'ectinstantaneous engagement and disengagement and to hold the partssecurely in their operated positions. lil/'hile the several operating`parts may be produced by any suitable method as for instance by casting,for economy of manufacture, they are preferably formed by sheet metalstamping as illustrated in the draW- ings. Likewise, for economy ofmanufacture, the movable arms 15, are made spring arms, and are includedin the electrical circuitto be opened and closed, it will be ob viousthat these arms may be made rigid and pivoted at their" lower extremity,and be made to carry either yielding Contact heads, a valve or a clutchoperating means as shown in the severaldetail views, Figs. 9, 1() and11. liilreivise, there has been shovvn in Figs. 6 and 7, means foroperating the bell crank lever by the rise and fall of a float or by thedistortion of a thermostatic bar, in lieu of the fluctuations of thediaphragm 3.

From the above description `it Will be apparent that there is thusprovided a device of the character described possessing the particularfeatures of advantage before enumerated as desirable, but Whichobviously is susceptible of modification in its form, proportions,detail construction and arrangement of parts Without departing from theprinciple involved or sacrilicingany of its advantages. y i

While in order to comply with Ythe statute the invention has beendescribed in language more or less specic as to structural features, itis to be understood that the invention is not limited to the specificdetails shown, but that the means and construction herein disclosedcomprises the. preferred form of several modes of putting the inventioninto effect and the invention is, therefore,claimed in any of its formsor modificationsWithin the legitimate and valid scope of the appendedclaims.

Having thus described my invention, I

claim:

1. `In a device of the character described, a pressure operated primemover, a cam member carried thereby having convergingl cam faces andcapable of limited to and fro movement `independent ofthe movement ofthe prime mover, an alternator member riding uponthe cam member,a springinclined to the path of travel of said alternator in differentdirections when the alternator is atl opposite limits of its stroke andfurther pressing an alternator memberinto engagement with first one, andthen the other of said converging `faces of the `cam member, saidconverging faces being alternately presented n engagement With analternator member by the movement of the prime mover, the independentmovement of the cam member serving to shift said member past dead centerposition, a member to be moved to alternate positions `connected `withsaid alternator member and pressure means controlling the movement ofthe prime mover.

2. In a device ofthe vcharacter described, a member to be moved toalternate positions, a pressure actuated main operating lever, a camlever pivoted concentric with the main lever, a looser coupling betweenthe main lever and the cam lever by which said levers are caused4 tomove in unison in either direction throughout the major pon tions oftheir strokes, but permitting a limited independent movement of saidlevers relative to each other, a reciprocatory actuating member springpressed into engagement With the cam lever and operatively connectedWith the member to be moved, the convergent cam faces of the cam leverbeing alternately presented in operative engagement with the actuatingmember by the `to and fro movement of the main lever and cam lever.

3. In a device of the character described, a member to be moved toalternate positions, a pressure operated prime mover, a cam membercarried thereby having convergent cam faces, said prime mover and cammember being movable to and fro in unison throughout the major range oftheir strokes butl capable of limited independent `Inovement relative toeach other, alternating actuating member for the member to be moved, aspring :pressing said alternating member into operative engagement withone -of the converging cam `faces of said cam member said alternati fractuating member beine movable to and nigio past dead center relationwith said spring whereby said spring is caused to act first inonedirection and then inthe other upon said alternating member, said camfaces being alternately presented in operative `relation with theactuating `member by the to and fro movement of the cam member to effectalternating shifting oi' the actuating member and with it the member tobe moved.

4:. In a device of the character described, the combination Witha memberto be moved to alternatev posi-tions, of an alternating actuating membertherefor, a double faced cam over which the actuating member rides inits alternating movement, 'a spring for effecting `operative `engagementof said alternating member with first one face and -then the other ofsaid `cam said alternating member being movable to and fro past deadcenter relation with said spring whereby the spring tends to hold saidalternating member at either limit of its stroke and pressure operated`means for relatively adjusting the'` cam `and alternating member toeil'ect reversal of. the member.

5. In a device of the character described, a member to be moved toalternate .positions, an actuating member there-tor., a cam memberhaving converging faces alternately in engagement with the actuatingmember, a` spring tending tomove the actuating member along the `engagedtace of the cam the actuating member being movable toizand fro past`dead center relation with said spring, and means for shitting the cammember `to present `the converging faces thereof alternately inengagement with the actuating member whereby the actuating member `Willbe moved alternately in reverse directions under infiuence of the springthe dead center position oi' said cam member and said spring beingpassed substantially simuitaneously Vby said? actuating member.

6. In a device of the character described,

rename a member` 'to `be moved tofalternate positions, a bell cranklever, one arm of which is channeled, .a cam lever concentricallypivoted witbthe bell cran-k lever and seating within the channeled `armofthe bell crank lever, means for limiting the relud tive oscillation ofthe cam lever and the bell crank lever beyond `the range of whichindependent movement smid levers move in unison, an actuating member forthe member to be `moved `having operative engagement with the cam`leven, in di'crenrt `positions oi' adjustment of the latter' to etlectshifting movement olf the actuating member in diferent directions, andmeans for oscillating the bell crank lever in alternate directimis.

7. In a device of the character described, a member `to be moved toalternate position-s, main operating lever, 4a cam lever pivotedconzcentricaily with the main operating lever, means for limiting therelative oscillation of the main lever and the cam lever beyond therange of which independent movement, the levers move iny unison, anactuating member for the member to be moved having operative engagementwith the cam lever in dili'erent-positions of adjustment of the latter',to effect shifting Inovement oi' the actuating member in differentdirections, and means for oscilllating -tlre main operating lever.

8. In a device oaf the character described, a member to be moved toalternate positions, a main operating lever, a camY lever pivotedconcentrically with the mainoperating lever, and having therein a recessand an extension upon the 4main Vlever projecting into said recess whichis ci snlcient extent to permit a limited degree of lost motion therein,beyond the range of which lost mot-ion the levers move in unison, anactuating member for til-'1e member to be moved having operativeengagement with the cam lever in different positions of justmentof thelatter, to eiect shifting movement ofi" the actuating member indifferent directions, and means for oscillating the main lever. i

In testimony whereof", -I have hereunto set my hand this 28th day ofSeptember A. D.

1925. P. LRSH.

